Allow marking of stubbed API via the 'info.yml' file

[alvsan09]

Following the discussion under:
eclipse-theia/theia#11100 (comment)

The 'info.yml' file in this repository is currently used to manually add 'notes' to specific API's, which are reflected in a 'notes' column
The discussion above proposes to use a similar mechanism via the 'info.yml' file with the following purpose:

"allowing to mark namespaces/types specifically as stubbed, so that they show up as warning (orange), meaning that the types are available but actually not functional".

[alvsan09]

As per the discussion below, the solution to mark API as stubbed has been moved to the corresponding theia.d.ts targets, see:
#32 (comment)

The solution is being implemented as part of #36
Therefore closing this issue.